Gold and tin of fluid-magmatic systems： causes of combination-separation of concentration elements

The aim of the investigation is to reveal possible causes of isolation and co-occurrence of the economically significant concentrations of gold and tin. Comparative analysis of the different-rank factors that influenced migration and concentration of these elements show that different geochemical properties of Au and Sn are responsible for isolation of their big concentrations giving rise to independent metallogenic provinces, zones, and ore nodes. These differences resulted in individualization of the element migration ways to the level of ore concentration within the fluid-magmatic columns. Three main factors influenced the Au and Sn migration activity: different patterns of metal connection with the melt structure, different relation with oxygen, and different relation with other strong oxidizers. By the moment when ore-bearing fluid became isolated from magmas, the metallogenic signature of the melts, contrasting in redox-potential, had already been defined that was confirmed by the fact that tin ores associate predominantly with the granitoids of ilmenite series and gold ores with those of magnetite series. The fluid-magmatic systemswith an intermediate degree of the melt reduction-oxidation may be considered the potential producers of the combined metal concentrations. In these cases, the combined concentrating of tin and gold is plagued by an opposite direction of the oxidation-reduction reactions when their most common minerals are formed: the main migration form of Sn+2 must be oxidized (with cassiterite portioning) , and the forms of Au+ or Au+3 must be reduced (with native gold portioning) . Probably, because of this the combined tin and gold concentrations are dominated by one of the metals with a tendency of accumulation in different-stage mineral complexes.     

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绝对重力仪中几种隔振系统的对比测试

介绍目前绝对重力仪中几种常用的隔振系统及其研究进展,并利用FG5-112绝对重力仪中的Super Spring以及现有的几种隔振系统,在相同的环境下进行对比测试。通过对测试结果的分析,给出各种隔振系统的隔振效果。该项工作的开展为下步自主研制隔振系统、提高隔振性能积累经验。     

Application of isolation forest to extract multivariate anomalies from geochemical exploration data

Constructing a statistical model that best fits the background is a key step in geochemical anomaly identification.But the model is hard to be constructed in situations where the sample population has unknown and/or complex distribution.Isolation forest is an outlier detection approach that explicitly isolates anomaly samples rather than models the population distribution.It can extract multivariate anomalies from huge-sized high-dimensional data with unknown population distribution.For this reason, we tentatively applied the method to identify multivariate anomalies from the stream sediment survey data of the Lalingzaohuo district, an area with a complex geological setting, in Qinghai Province in China.The performance of the isolation forest algorithm in anomaly identification was compared with that of a continuous restricted Boltzmann machine.The results show that the isolation forest model performs superiorly to the continuous restricted Boltzmann machine in multivariate anomaly identification in terms of receiver operating characteristic curve, area under the curve, and data-pro-cessing efficiency.The anomalies identified by the isolation forest model occupy 19％of the study area and con-tain 82％of the known mineral deposits, whereas the anomalies identified by the continuous restricted Boltz-mann machine occupy 35％of the study area and contain 88％ of the known mineral deposits.It takes 4.07 and 279.36 seconds respectively handling the dataset using the two models.Therefore, isolation forest is a use-ful anomaly detection method that can quickly extract multivariate anomalies from geochemical exploration data.     

中国食管癌与土壤环境中元素的相关性

利用土壤元素资料 2 0 6 94 4 8个数据 ,食管癌死亡调查资料 1750 80例 ,研究了食管癌死亡率与人群生存的土壤环境中元素的相关性。结果表明 ,铅、硒、铷、铯、镁、钙、镓、铊、钍、铀、锡、铪、铋、钼、溴、碘元素与食管癌死亡率有相关性     

基于PID反馈的两级超低频隔振系统理论分析及仿真

建立两级隔振系统的运动模型,推导系统的闭环传递函数并对传递函数进行分析。结果表明：1）系统采用PID反馈较当前超长弹簧中采用的PD反馈具有更好的等效阻尼系数调节功能。2）系统的等效固有周期主要受反馈比例系数kp影响,kp越大,等效固有周期越长,隔振效果越好;kp选定后,积分系数ki和微分系数kd共同影响系统的阻尼,且ki占主导地位,决定系统的稳定性。通过仿真验证了闭环传递函数分析结果的准确性,且仿真结果表明,系统在1 Hz处的隔振效果可达-70 dB。     

A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin (each at a concentration of 600 mg/L) for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains of Nannochloropsis sp. (Eustigmatophyceae), two strains of Cylindrotheca sp. (Bacillariophyceae), two strains of Tetraselmis sp. (Chlorodendrophyceae) and one strain of Amphikrikos sp. (Trebouxiophyceae) were purified successfully. The method shows promise for batch-purifying microalgal cultures.     

Genetic structure and demographic histories of two sympatric Culter species in eastern China

Geographic isolation is a key factor in shaping the genetic structure of many fish species.Two sympatric species,Culter alburnus and C.mongolicus,are economically important fish that are widely distributed in China and have been recently used as new aquaculture species.We used the mitochondrial DNA control region(CR) as a marker to investigate the genetic structure of the two species.Phylogenetic analysis revealed two major lineages(Lineages I and II) that were highly consistent with geographical patterns for C.alburnus and C.mongolicus.Based on genetic distance,the Zhujiang(Pearl) River Basin(ZRB) populations potentially represented a cryptic subspecies,which might be differentiated as the result of strict geographic isolation,an earlier diverged event,or peripheral areas.Genetic diversity analysis suggested that the Changjiang(Yangtze) River Basin(CRB) populations are located at,or near the core region of their origination,not only due to the larger population size at the CRB,but also their habitat diversity and suitability for its survival,and the genetic diversity dif ferences among basin populations were significant for the two species.Moreover,demographic analysis indicated that the two Culter species and most populations had undergone a period of population expansion during warm interglacial periods.However,the C.alburnus population of Huaihe River Basin(Weishan Lake) exhibited different patterns during the interglacial period,which may due to the latest diverged time of HRB and Weishan Lake located at the permafrost.Notably,the ZRB(in Songtao Reservoir) C.mongolicus population showed no genetic diversity and had a unique haplotype,which could be treated as a special gene pool for species conservation.In summary,geographic isolation is most likely responsible for the two Culter species distribution patterns.     

Research on influencing factors of coupling in SIMO antenna

In the process of radar data acquisition, limited amount of information can be provided to postprocessing interpretation by the data acquisition method of single-input and single-output, however, the location and physical parameter information of geological body can be obtained more accurately by using Multi-Input Multi-Output(MIMO) antenna with multiple transmitters and multiple receivers. Especially when collecting borehole radar data and the aperture is very narrow, but the antenna is require...     

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山羊传染性胸膜肺炎的诊断及组织灭活茵免疫效果观察

通过流行病学调查、临床症状、病理剖检及病原分离等方法诊断雷州山羊传染性胸膜肺炎 ,证实肺、肺门淋巴结、胸水及纵膈淋巴结是山羊霉形体感染的主要靶组织 ,用病变组织制备的组织灭活苗对霉形体感染具有良好的免疫保护性     

Isolation of Chloroplasts from Marine Microalga Isochrysis galbana Parke for Their Lipid Composition Analysis

Marine microalga Isochrysis galbana is an important feed species with a high nutritional value.Different from other uni-cellular algae,its cell contains two chloroplasts which are the major sites for lipid synthesis.Here,we optimized a chloroplast isola-tion approach suitable for the isolation of I.galbana chloroplasts and determined the purity and integrity of the isolated chloroplasts through microscopic observations and enzyme activity assay.The chloroplast lipids were analyzed with a ultrahigh-performance li-quid chromatography-Q Exactive Orbitrap-mass spectrometry.This newly developed isolation approach is simple and reliable to isolate chloroplasts with high integrity and purity.The average yield of intact chloroplasts was 15.3%±0.1%.Glycolipids and acyl-glycerols were the main chloroplast lipids.Glycolipids accounted for 56.6%of chloroplast lipid.Digalactosyldiacylglycerol(DGDG),monogalactosyldiacylglycerol(MGDG)and sulfoquinovosyldiacylglycerol(SQDG)were the main glyceroglycolipids.The fatty acyl R1/R2 were mostly 18:4/16:1,18:3/16:1 and 18:4/18:5 in DGDGs,14:0/18:4,18:4/18:5,18:4/18:4 and 18:3/18:4 in MGDGs and 16:0/14:0,16:0/18:3,and 18:4/18:3 in SQDGs.In addition,diacylglycerol(DAG)was the most abundant acylglycerols;the content of 22:6/18:4-DAG was the highest.There was a little amount of glycosphingolipid(GSL)in chloroplast.Digalactosylmonoglyceride(DGMG),monogalactosylmonoglyceride(MGMG),sulfoquinovosylmonoacylglycerol(SQMG),monoglyceride(MAG),phospholi-pids(PLs),ceramide(Cer)and betaine lipids were nearly undetectable in chloroplast.The fatty acid proportions of DGDGs,MGDGs,SQDGs,DAGs,triglycerides(TAGs)and GSLs were either higher or lower than or similar to those of whole-cell.Collectively,our isolation approach is applicable to many aspects of chloroplast biology,and may offer a reference for the isolation of chloroplasts from other marine microalgae.     

Isolation and callus formation of Gracilariopsis bailiniae (Gracilariales,Rhodophyta) protoplasts

Journal of Oceanology and Limnology - This paper reports the first successful isolation of protoplasts from Gracilariopsis bailiniae and their callus formation. The base solution type,...     

平菇多糖的提取工艺

对平菇多糖提取进行优化研究 ,结果表明 ,平菇多糖提取最佳工艺条件为 :90℃浸提 8h ,m(原料 )∶m(水 ) =1∶30 ,醇析时乙醇体积分数为 80 % ,去除蛋白质时V(粗提液 )∶V(氯仿 +正丁醇 ) =1∶1,V(氯仿 )∶V(正丁醇 ) =10∶3,萃取 30min效果最佳 ,其得率为 1.5 4%。     

High efficiency of protoplast preparation for artificially cultured Ulva prolifera (Ulvophyceae,Chlorophyta)

Journal of Oceanology and Limnology - Protoplast isolation was relevant for gene manipulation in Ulva, and universal protocols have been proposed based on evaluation for various wildly collected...     

深圳市快速抑制COVID-19疫情的非药物干预措施效果评估：基于智能体的建模研究

在2020年COVID-19第一波疫情中,通过一系列非药物干预措施,国内许多城市实现了疫情的快速抑制。对这些交叉叠加的多项干预措施进行单项措施的效果评估,识别出关键的防控策略,能够为未来的疫情防控提供重要的经验与科学依据。本研究以深圳市为例,利用融合了多源时空轨迹大数据的空间显式智能体模型评估深圳市快速抑制第一波疫情的各项非药物干预措施效果,识别出核心措施与辅助措施。模拟结果显示,在深圳市第一波疫情中,单项干预措施有效性从高到低依次为居家令、综合隔离、佩戴口罩与分批复工。其中,居家令或综合隔离均能有效抑制疫情的大范围暴发,被本研究称之为核心措施;佩戴口罩或分批复工则只能从不同程度上降低总体感染规模并延缓疫情峰值,并不能抑制疫情暴发,被本研究称之为辅助措施。考虑到社会经济成本以及常态化防疫中人群依从性降低,本研究建议在COVID-19 散发疫情防控中将核心措施与辅助措施相结合,重点实施各项隔离措施,同时将外出佩戴口罩作为疫情常态化防控手段。此外,本研究展示了结合时空大数据与智能体模型精细化模拟城市内部传染病扩散过程的优势：不仅能在城市内部高精度推演疫情发展过程,而且能够支撑评估面向个体及各类型出行活动的非药物干预措施实施效果,为制定针对性、精细化的“时间-空间-人群”防控策略提供重要的科学依据。     

氮、磷、硅对条纹小环藻生长和叶绿素a含量的影响

采用单因子实验方法研究氮、磷和硅营养盐对条纹小环藻(Cyclotella striata)生长和叶绿素a含量的影响。结果表明:在不同磷和硅营养盐浓度下,条纹小环藻比生长率μ变化显著(P<0.05),其中,硝酸盐为0.60~0.85 d-1,硅酸盐为0.49~0.61 d-1,磷酸盐为0.46~0.51 d-1。总体而言,在一定的营养盐浓度范围内,条纹小环藻的最大藻细胞密度Nmax随着氮、磷和硅营养盐浓度的增加而增大;条纹小环藻叶绿素a(Chl a)含量亦随着氮、硅浓度的增加,与Nmax增加趋势一致,但随着磷浓度的增加Chl a先增加后减小,与Nmax不一致。条纹小环藻的主要限制营养元素是氮和硅,而磷可能不会成为其短期培养的限制因子。     

The origin,historical variations,and distribution of heavy metals in the Qiongzhou Strait and nearby marine areas

We analyzed heavy metal concentrations in a number of surface sediments and cores from the Qiongzhou Strait and surrounding marine areas.The areas of high concentrations are primarily outside the eastern mouth of the Qiongzhou Strait and on the west side of the Leizhou Peninsula,whereas the areas of low concentrations are located primarily in the eastern Qiongzhou Strait.The maximum Cd,Pb and Zn concentrations in the samples collected in our study do not exceed the official standards for marine sediments,whereas the concentrations of Cr and Cu slightly exceed the standards.Correlations exist between the concentrations of Cu,Pb,Zn,Cr and Cd,and the concentrations of these metals are positively correlated with the mean particle size(φ value),indicating that the finer sediments have adsorbed greater amounts of heavy metal elements than the coarser sediments.An evaluation of the potential environmental risks demonstrates that certain indices of heavy metal pollution and environmental risks are relatively low and may be assigned low risk levels,thereby indicating that,in terms of heavy metals,the marine sedimentary environment in this region is only mildly impacted.Our analysis of the contaminant origins shows that the heavy metals in this region primarily originate in the Pearl River Estuary and that a small amount of them is derived from local runoff.The elevated heavy metal concentrations from the upper sections of the cores started 130 years ago,which indicats that heavy metals in the surface sediments are primarily due to human activities associated with industrialization.     

大肠杆菌内毒素引起肉鸡腹水症的诊治

头面部肿胀、下痢、腹水、腹腔纤维素性渗出及肝脏周围炎、腹膜炎是大肠杆菌内毒素引起的肉鸡腹水症的主要特征,通过临诊症状、病理剖检及细菌分离确诊本病,采用环境消毒及抗生素治疗可有效控制本病.     

Cultural characteristics of chromium resistant unicellular cyanobacteria isolated from local environment in Pakistan

Many unicellular cyanobacteria were isolated from different places： fields, ponds, polluted water, and soils from Muredkey and Kasur tannery areas, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu＇s # 10 medium and Gotham＇s medium, in standard forms and with slight variations of ingredients, and different pH, temperature and light regimes were checked for the optimum growth of the isolates. The isolation pro- cedure was repeated with different concentrations of chromium to select the resistant strains. These selected strains grew on chromium of the range 100-200 μg/ml in BG 11 medium. Cyanobacteria were maintained in solid and liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan, and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of unicellular cyanobacteria. Resistance of these strains against different heavy metals （ZnSO4, MnSO4, NiSO4, COCl2, Pb（NO3）3, CuSO4, HgCl2, AgNO3 and CdCl2） and antibiotics （erythromycin, streptomycin, kanamycin, chloramphenicol, neomycin） was evaluated. Optimum temperature was 30℃ with variable pH for the reduction of Cr^6＋ in to Cr^3＋ in majority of strains.